Toxic eftect of various concentrations of Lead (2, 4, 8, 10, 16, 20 mg/mL) on some gram +ive and gram -ive bacteria is reported in this study. Lead inhibited the growth of gram +ive Staphylococcus areas and Bacillus cereus as well as gram -ive bacteria Salmonella typhi and Escherichia coli. The area of the zone of inhibition was directly proportional to the concentration of Pb. Gram -ive bacteria were more susceptible to Lead than gram +ive bacteria.